Image display apparatus for radiation diagnosis

Abstract

Image data of a plurality of frames obtained upon irradiating a radiation onto an object to be examined, the object being injected with a catheter in a blood vessel thereof, are converted into digital image of a plurality of frames by an A/D. Digital image data of a first predetermined frame and digital image data of a second predetermined frame prior to the first predetermined frame, which are converted by the A/D, are alternately stored in first and second memories. A difference between the digital image data of the first predetermined frame output from the A/D and the digital image data of the second predetermined frame output from the one of first and second memories is calculated by a subtractor to obtain subtraction image data denoting a motion of the catheter. This subtraction image data is multiplied by a multiplier with a predetermined weighting factor input by a console to emphasize the subtraction image data, thereby displaying subtraction image data emphasized in correspondence with the catheter motion on a TV monitor.

What is claimed is: 
     
       1. An image display apparatus for radiation diagnosis, comprising: radiation detector means for obtaining image data;   image input means for inputting image data of a plurality of frames obtained by irradiating a radiation onto a patient to be examined, the patient being injected with a catheter in a blood vessel thereof;   emphasizing means, responsive to said image input means, for processing the image data so as to emphasize a difference between image data of first and second predetermined frames in the input image data;   display means, responsive to said emphasizing means, for displaying the emphasized image data which is processed by said emphasizing means; and   said emphasizing means comprising: subtracting means, responsive to said image input means, for calculating a difference between image data of first and second predetermined frames of the image data of the plurality of frames input from said image input means, and for obtaining subtraction image data;   first filter means, responsive to said subtraction means, for extracting a frequency component higher than a first predetermined frequency of the subtraction image data from said subtracting means;   calculating means, responsive to said first filter means, for processing the subtraction image data extracted from said first filter means by using a predetermined weighting factor, and for weighting the subtraction image data; and   adding means, responsive to said calculating means and said second filter means, for adding the subtraction image data weighted by said calculating means and the image data input from said image input means.     
     
     
       2. An apparatus according to claim 1, in which the second predetermined frame precedes the first predetermined frame by one frame. 
     
     
       3. An apparatus according to claim 1, in which the radiation consists of X-rays. 
     
     
       4. An apparatus according to claim 1, in which said subtracting means comprises: a subtractor, responsive to said image input means, for calculating a difference between image data of a first predetermined frame of the image data of the plurality of frames input from said image input means and image data of a second predetermined frame, and for obtaining subtraction image data; and   a comparator, responsive to said subtractor, for comparing the subtraction image data from said subtractor with a predetermined value to obtain subtraction image data smaller than the predetermined value.   
     
     
       5. An apparatus according to claim 1, in which said subtracting means comprises: an average circuit, responsive to said image input means, for averaging image data of several frames input from said image input means; and   a subtractor, responsive to said image input means and said average circuit, for calculating a difference between image data of a first predetermined frame input from said image input means and image data of a second predetermined frame input from said average means to obtain the subtraction image data.   
     
     
       6. An apparatus according to claim 1, said apparatus further including: second filter means, responsive to said calculating means and said image input means, for adding the subtraction image data weighted by said weighting means and the image data input from said image input means; and   said adding means being responsive to said calculating means and said second filter means to add the subtraction image data weighted by said calculating means and the image data extracted by said second filter means.   
     
     
       7. An image display apparatus for radiation diagnosis, comprising: radiation detector means for obtaining image data;   image input means for inputting image data of a plurality of frames obtained by irradiating a radiation onto a patient to be examined, the patient being injected with a catheter in a blood vessel thereof;   emphasizing means, responsive to said image input means, for processing the image data so as to emphasize a difference between image data of first and second predetermined frames in the input image data;   display means, responsive to said emphasizing means, for displaying the emphasized image data which is processed by said emphasizing means; and   said emphasizing means comprising: subtracting means, responsive to said image input means, for calculating a difference between image data of first and second predetermined frames of the image data of the plurality of frames input from said image input means, and for obtaining subtraction image data;   comparing means, responsive to said subtracting means, for comparing the subtraction image data from said subtracting means with a predetermined value to obtain subtraction image data including image data included in one of the first and second predetermined frames that is newer but not included in the other of the first and second predetermined frames;   calculating means, responsive to said comparing means, for calculating the subtraction image data from said comparing means and a predetermined weighting factor and for weighting the subtraction image data; and   adding means, for adding the subtraction image data weighted by said calculating means to said image data from said image inputting means.     
     
     
       8. An apparatus according to claim 7, in which the second predetermined frame precedes the first predetermined frame by one frame. 
     
     
       9. An apparatus according to claim 7, in which said subtracting means outputs subtraction image data having pixel values falling within a range of -100 to +100. 
     
     
       10. An apparatus according to claim 9, in which the predetermined value in said comparing means is a predetermined value falling within a range of -100 to 0. 
     
     
       11. An apparatus according to claim 7, in which the radiation consists of X-rays. 
     
     
       12. An apparatus according to claim 7, in which said subtracting means subtracts an older one of said first and second frames from a newer one and said comparing means obtains subtraction image data smaller than the predetermined value. 
     
     
       13. An apparatus according to claim 7, in which said subtracting means subtracts a newer one of said first and second frames from an older one and said comparing means obtains subtraction image data larger than the predetermined value.